Artifacts reduction in high-acutance phase images for X-ray grating interferometry.

X-ray grating-based techniques often lead to artifacts in the phase retrieval process of phase objects presenting very fast spatial transitions or sudden jumps, especially in the field of non-destructive testing and evaluation. In this paper, we present a method that prevents the emergence of artifacts by building an interferogram corrected from any variations of the object intensity and given as input in the phase retrieval process. For illustration, this method is applied to a carbon fiber specimen imaged by a microfocus X-ray tube and a single 2D grating. A significant reduction of artifacts has been obtained, by a factor higher than 10. This evaluation has been performed experimentally thanks to the Confidence Map tool, a recently developed method that estimates the error distribution from the phase gradient information.